In recent years, utility tunnels, as an important part of the sustainable development of urban underground space, are developed rapidly, and buried pipelines such as pipelines for electricity, communication, gas, water supply, drainage, heat, and television network are set in the utility tunnel in the same tunnel space. The utility tunnel has the advantages of high levels of modernization and intensification, and is easy to be collaboratively maintained and intensively managed. However, the local uneven settlement will inevitably occur due to long longitudinal sections of the utility tunnel structures, which leads to pipeline fractures and causes hazards like fires or even explosions. Therefore, timely and accurate acquisition of local uneven settlement information of the utility tunnel is of great importance. Monitoring the relative settlement of the settlement joints of the utility tunnel in real-time allows the warnings of the over-limit part being provided in advance, which will control the excavation speed of a foundation and precipitation speed during the development of the surrounding area, and prevent accidents by avoiding damaging pipeline in the utility tunnel. Fiber Bragg grating is suitable for well long-term monitoring of complex underground projects due to characteristics of high sensitivity, anti-electromagnetic interference and corrosion resistance. Necessarily, a high-precision fiber Bragg grating dislocation sensor should be developed for long-term and real-time monitoring of the relative settlement state of the settlement joints of the utility tunnel.